Ozone is formed in the atmosphere by the action of sunlight, ultraviolet light or an electrical discharge such as lightning on oxygen in the air. It is also formed when an electrical apparatus produces sparks in the air.
Ozone in the air may be toxic to human beings and animals. According to Occupational Safety and Health Administration (OSHA), the permissible maximal average concentration of ozone in the air should be no more than 0.1 ppm when breathing air. Many apparatuses for industrial use are manufactured in accordance with these standards. Ozone has a characteristic odor, which is noticeable even at concentrations as low as 0.01 to 0.02 ppm. When the concentration of ozone increases to about 0.05 ppm, it has an unpleasant odor; and when the concentration exceeds 0.1 ppm, it is irritating to the mucous membranes of the eyes and respiratory organs. Ozone is also a powerful oxidizing agent which oxidizes and deteriorates organic materials. Therefore, it is desirable that the concentration of ozone be kept as low as possible.
Ozone is used in industry for the sterilization, deodorization and decolorization of water and for the treatment of raw sewage. These applications often require the use of ozone in concentrations as high as 500-2500 ppm. For example, to sterilize water, 1 to 3 g of ozone is bubbled into 1 cubic meter of water. Most of the ozone blown into water is decomposed, however, some of the residual ozone can be discharged from the water into the air. Since the concentration of the discharged ozone in the air may be as high as 1 ppm, it is necessary to decompose the discharged ozone before it spreads into the air for the safety to human beings and for the protection of the environment.
Since ozone is toxic to human beings when its concentration in the air is high, various methods have been proposed to decrease its concentration. For example, filters made of activated carbon and filters containing various catalysts, such as metal oxides of manganese, copper, silver and cobalt, have been employed for decomposing ozone. If the density of the materials in these filters is high, the absorption of ozone and its decomposition efficiency is increased. However, the higher density of these materials slows the flow rate of the air through the filter. By contrast, if the density of the materials in the filter is decreased, the absorption of ozone and the ozone decomposition efficiency are decreased.
Various polymers and terpenoid compounds have also been used to control ozone levels. For example, a rubber olefin polymer containing double bond groups has been used for decomposing ozone generated from an electrophotographic copying machine. Terpenoid compounds capable of decomposing ozone, such as linalool, linalool ester, citral and the like, in various solutions and gels have also been used. In addition, paints containing a variety of organic materials have been proposed. However, the decomposition efficiency is not high enough for use in practice. Furthermore, the by-products formed after decomposition of the ozone has not been fully characterized in these cases. Therefore, it is unclear whether exposure to these by-products affect a person's health, and whether there are any negative environmental impacts.
Therefore, there remains a need in the art for new compounds, compositions and methods for removing and/or controlling ozone levels without having a negative impact on humans, animals and the environment, wherein the by-products formed after decomposition of the ozone is safe and fully characterized.